<!DOCTYPE html>
<html>

<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .nav {
            height: 30px;
            background: #036663;
            border-bottom: 1px solid #369;
            line-height: 30px;
            padding-left: 30px;
        }

        .nav a {
            color: #fff;
            text-align: center;
            font-size: 14px;
            text-decoration: none;

        }

        .d-box {
            width: 400px;
            height: 300px;
            border: 5px solid #eee;
            box-shadow: 2px 2px 2px 2px #666;
            position: absolute;
            top: 40%;
            left: 40%;
        }

        .hd {
            width: 100%;
            height: 25px;
            background-color: #7c9299;
            border-bottom: 1px solid #369;
            line-height: 25px;
            color: white;
            cursor: move;
        }

        #box_close {
            float: right;
            cursor: pointer;
        }
    </style>
</head>

<body>
    <div class="nav">
        <a href="javascript:;" id="register">注册信息</a>
    </div>
    <div class="d-box" id="d_box">
        <div class="hd" id="drop">注册信息 (可以拖拽)
            <span id="box_close">【关闭】</span>
        </div>
        <div class="bd"></div>
    </div>
    <script>
        // 鼠标点击drop后,drop就跟随鼠标移动;不点击就不跟随.
        var drop = document.querySelector('#drop');
        var box = document.querySelector('#d_box');
        drop.addEventListener('click', function () {
            document.addEventListener('mousemove', function (e) {
                var x = e.pageX + 'px';
                var y = e.pageY + 'px';
                box.style.left = x;
                box.style.top = y;
            })
        })

    </script>
</body>

</html>